


Family Don't End with Blood

by Lightwood3



Category: The Shadowhunter Chronicles - All Media Types
Genre: Alec Lightwood Deserves Nice Things, Bad Parent Maryse Lightwood, Bad Parent Robert Lightwood, Bad Parent Valentine Morgenstern, Child Abuse, Emotional Hurt/Comfort, Fluff, Fluff and Hurt/Comfort, Gen, Good Sibling Isabelle Lightwood, Hurt Alec Lightwood, Hurt Jace Wayland, Hurt/Comfort, Implied/Referenced Child Abuse, Jace Wayland Deserves Nice Things, Jace Wayland Feels, Jace Wayland Needs A Hug, Jace Wayland is a Lightwood, Lightwood Siblings, Lightwood Siblings Feels, Nightmares, Parabatai, Past Child Abuse, Protective Isabelle Lightwood, Protective Siblings, Sibling Bonding, Sibling Love, Siblings, Supportive Isabelle Lightwood, Twins, Worried Isabelle Lightwood
Language: English
Status: Completed
Published: 2021-03-10
Updated: 2021-03-10
Packaged: 2021-03-16 19:54:41
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,579
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29955069
Author URL: https://archiveofourown.org/users/Lightwood3/pseuds/Lightwood3
Summary: Jace just arrived at the New York Institute after being placed with the Lightwood family. He meets twins Alec and Isabelle, and learns that his new parents might not be so different from his old. Despite his best efforts to close himself off from the world around him, watching Alec and Isabelle love each other makes him think that maybe he wouldn't mind having something like that too...NOTE: MENTIONS OF CHILD ABUSE
Relationships: Alec Lightwood & Isabelle Lightwood, Alec Lightwood & Isabelle Lightwood & Jace Wayland, Alec Lightwood & Jace Wayland, Isabelle Lightwood & Jace Wayland
Kudos: 4





	Family Don't End with Blood

**Author's Note:**

> (I know the title is a Supernatural reference, not Shadowhunters, but it fit so...)
> 
> This is my very first time ever posting a fanfic online! I've written a few of them, but this one seemed like a good fit for my first post. I'm a bit nervous about sharing them publicly, but please feel free to leave me some feedback! I have a general background story I work off of, as well as some canon that I've altered for my stories. If you think it would be helpful for me to post a blanket document that spells all that out, please let me know! 
> 
> Enjoy!

Jace was sent to the New York Institute, where he had been placed with the Lightwood family. He was still reeling from watching his father die before his eyes and completely closed himself off, not that things would have been different either way. He grew up completely alone, just him and Valentine. Sometimes various Circle members would hang around, but there were never any other children. 

When he arrived at the Institute, everyone avoided him, not wanting to associate themselves with the son of a monster. Even Robert and Maryse Lightwood were cold and distant. The only ones who attempted to befriend him were the Lightwood twins, Isabelle and Alec. Jace was like a shell of a person; he wouldn’t talk to them unless he absolutely had to, and he only looked at them in secret. Sometimes, he would crouch into a neighboring room or closet, draw various spying runes on the walls, and watch them interact with each other. He wasn’t trying to be a creep, he just wanted to understand them without letting them in on it. He knew that the twins’ relationship wasn’t like anyone else’s. Though he didn’t know many other kids his age, he did know that twins were rare, and that they shared a special connection that was hard to compare to anything other than a parabatai bond. Isabelle and Alec loved and cared for each other more than normal siblings do. However, after spending some time with their family, he realized it their connection came from much more than the bond they were born with.

Valentine was a monster, sure, but when it came to parenting, Maryse and Robert were almost as bad. They beat their children violently and without good reason, but in far less creative ways. They shared Valentine’s rule that injuries from their punishments were never to be healed by iratze; that their children needed to feel the lingering (and sometimes scarring) consequences of their actions. Jace was disturbingly comforted by the Lightwoods’ expectations for perfection, and their intolerance for anything but. Like Valentine, they believed that “to love is to destroy, and to be loved is to be destroyed”, which only made it easier for them to deliver their harsh punishments. Jace, too, always followed that saying, but it never stopped Isabelle and Alec from loving each other fiercely. Both siblings knew what was expected of them: work hard, uphold the law, and honor the Lightwood name. Whenever they failed to meet their parents’ unrealistically high expectations, they were met with their wrath, finding comfort only in each other. Jace was surprised at how similar their upbringing had been to his own, except his father was ten times more twisted and evil, and never showed an ounce of mercy. The biggest difference however, at least to Jace, was that he had been forced to suffer alone and in silence, completely cut off from the rest of the world. 

~*~*~

Today had been the worst since his arrival. During training, he decimated Alec without thinking about what that would mean for the clumsy, black-haired kid. He couldn’t shake the look in Alec’s eyes as he laid on the floor defeated. The Lightwood boy was drenched but Jace had barely broken a sweat. Robert stormed over and grabbed Alec by his collar, dragging him out of the room. Jace observed the way Isabelle’s body tensed, knowing all too well what was about to happen. Alec was punished far more often than she was, and each time she wished she could take his place. Like Jace, she was naturally gifted, but Alec was far from it. He had to fight tooth and nail to try and meet his parent’s expectations, and almost always came up short. The further from perfection he fell, the worse his punishment. Isabelle clenched her fists and locked her jaw, fighting back the overwhelming need to save her brother. Jace felt a chill rush through him when he saw the way Isabelle looked at her father. It was a look of pure hatred, with a fiery determination that she would one day kill him for this. 

Jace stood frozen as Isabelle collapsed to the ground in pain. She could feel every blow from her father as if it was landing directly on her. If Robert had activated Alec’s twinning rune before he began, then she would also show his wounds. But her father never did, believing that since only Alec had failed him, his scars were his to bear alone. 

As soon as Isabelle could stand, she ran to find her brother. Jace cautiously followed behind, ducking into the supply closet that neighbored the twins’ bedroom. He drew runes on the joining wall that allowed him to see and hear inside. 

Alec was curled up on his side sobbing as blood ran from the deep gashes on his back; his face was purple and swollen. Isabelle grabbed a few things from her bedside drawer before running to her brother’s side and carefully tending to his wounds. Jace was surprised at how expertly she healed him, easily rivaling the nurses in the infirmary. He assumed she had spent much of her free time secretly watching them work so that she could learn to properly tend to whatever Robert might do to Alec. 

After she had successfully stopped the bleeding and reduced the swelling on his face, she gently cradled her brother in her arms. Silent tears streamed down her cheeks. Alec pulled her arms tighter around him, despite the pain he knew it would cause; her love was worth every ounce of the sting. Jace felt his heart constrict at the sight. He couldn’t watch anymore, retreating to his room in solitude.

~*~*~

Every night, Jace drew silencing runes on his door before falling asleep. He didn’t want anyone to hear the screams that erupted from his nightmares. Each time he woke up in a sweaty panic, his first thought was about that interaction between Isabelle and Alec. The way she held him like he was the most precious thing in the world; the way he clung to her vulnerably and without shame. He wanted that. He _needed_ that. He was terrified by how weak it made him feel. He had never needed or wanted anyone’s help before.

The next time he was jolted awake from his haunting memories, he felt an overwhelming urge to reach out to Isabelle. He convinced himself that there was no harm in at least checking to see if she was awake. He texted her, trying to keep his message vague. No matter how vulnerable he felt right now, he knew he would definitely regret his actions in the morning. 

“Are you awake?” his fingers typed before he hesitantly pressed send. Seconds later his phone pinged, “Yeah, I can’t sleep. What’s up?” Her immediate response made him tense. _Retreat. Retreat._ He frantically tried to conjure up a lie, but his mind was blank. He froze when another message quickly followed, “Is everything okay?” He could hear her concern as if she had said it aloud. _Idiot._ Why did he text her? He couldn’t breathe, paralyzed by his inability to come up with a convincing response.

Moments later he heard footsteps approaching his door. _Fuck. Fuck!_ He braced himself. Robert and Maryse must have found out he texted her and were coming to teach him a lesson. 

The door slowly opened, his face turning pale as a ghost when he saw Isabelle standing before him. She noticed the sweat dripping from his temple and the silence rune traced on his door. “Alec gets them too,” she said softly. Jace tried to pretend like he didn’t know what she was talking about, but it was clear she wasn’t buying it. “I’m sorry for intruding but after you texted me, I had to make sure you were okay.” Jace just stared at her, he didn’t know what to say. “Can I come sit with you?” she asked cautiously. He slowly nodded with permission. She climbed in next to him, trying not to get too close. 

The blonde boy turned his head away hoping she wouldn’t see how scared he was. But she didn’t need to see his face to know it; he was shaking, his breaths were fast and shallow. She gently placed her hand on top of his. He pulled away, startled by her touch, his cheeks red with embarrassment. “It’s okay, Jace, I’m not gonna hurt you,” she assured him. He knew that, but he was nervous. No one had ever cared about him before. She tried again. This time he didn’t pull away, even as she proceeded to lace her fingers between his. Isabelle was surprised when she felt his grip tighten. She proceeded with caution, gently resting her head against his shoulder. 

Jace panicked as he felt a tear slide down his cheek without permission. He had never cried in front of anyone but Valentine, who had only punished him harder when he did. By the age of 6 he had trained himself to control it. He didn’t understand how that drop had escaped, or the ones that followed. Isabelle knew what was happening but waited until she heard him sniffle before wrapping her arms around him. As much as he had wanted this, he tried to push her away, so sure he would be punished for letting himself be so vulnerable. She didn’t budge, holding him tight until he gave up on fighting her. When his body relaxed it was like a dam broke, one that had been holding back four years’ worth of tears. He began sobbing uncontrollably, burying his head into her chest. He was overwhelmed with comfort, something he had never experienced in his long ten years of life. She calmingly ran her fingers through his hair. The mixture of her firm grip and gentle touch was intoxicating. There was no going back now. 

Eventually Jace’s sobs had drifted away, replaced by low, hummed breaths. He had fallen asleep. Isabelle smiled and laid back, allowing him to sleep on her chest. She pressed a gentle kiss to his head before closing her eyes. 

The next morning Jace slowly blinked his eyes open, met by an unfamiliar presence. He looked up to see Isabelle’s sleeping face. Last night’s events came flooding back to him and he was surprised by his lack of regret. Even as she slept, she had never let go of her tight grip around him. He smiled and laid his head back down. He didn’t dare move, he wanted to stay like this forever. 

~*~*~

After that night, Jace didn’t hesitate to ask for her help. It got to the point he began to wonder how he’d ever survived so many years on his own. Eventually, he opened up to Alec too, but it wasn’t quite the same. Alec didn’t have the same raw instinct that Isabelle possessed, like she knew exactly what he needed without him even knowing it himself. 

“I swear, sometimes it’s like she’s inside my head,” Jace confessed as he sparred with Alec. “Trust me, I know what you mean,” Alec agreed, lunging at Jace. Jace dodged him. “Yeah, but you guys are twins. You literally share a soul. How does she do that me?” He took a second to catch his breath before continuing, “From the first day I came to live with you, no matter how hard I shut you both out, she saw right through me like she’d known me her whole life.” His sword clashed against Alec’s. “Izzy is overly empathetic, always has been. For as long as I can remember she’s had this hypersensitivity to people’s thoughts and feelings. She can recognize the slightest change in someone’s breathing or heartbeat, see even the smallest tense of their muscles. I used to call it her superpower, but sometimes it’s more of a curse…” Alec trailed off. Jace took the opportunity to sweep his legs out from under him, knocking the black-haired boy on his back. 

Jace jumped on top of him, holding a blade to his throat. “Even if she can tell how I _feel_ , how does know what I _need_?” Jace questioned, as if he had been dwelling on it for quite some time. Alec laughed, disarming him, and reversing their positions. “You really don’t see it, do you? You two are exactly the same! I may be her twin but that means we’re two halves of one person, opposites in almost every way. But _you_ … you’re like a mirror; a perfect reflection of her. She knows you because she knows herself.” Jace just stared at the ceiling, the wheels in his head turning so hard Alec could almost hear them squeak. He patted Jace’s face tauntingly before climbing off of him. 

Even with Alec gone, Jace didn’t stand up. He just laid there for a while as he sorted his thoughts. 

~*~*~

The silence in the room was deafening. Jace accidentally lost control of his anger, and the three kids stood perfectly still, in terrified anticipation of what would happen next. He had snapped back at Robert, and the look in their father’s eyes said that he was about to put the golden-haired boy through hell. Isabelle and Alec held their breath as he grabbed Jace’s arm and yanked him out the door. The twins counted to 100 before running and hiding in their bedroom, which was directly across from Jace’s. They waited until they heard Robert leave before sneaking into the young boy’s room and drawing lock and silence runes on his door. 

Jace sat at the edge of his bed, his expression blank like his mind was far, far away. Isabelle treated his injuries, and as gentle as she was, his silence and stillness was alarming. “Jace, are you okay?” Alec asked concerned, but too scared to touch him. There was no response, it was like he didn’t even hear him. Isabelle and Alec exchanged a worried glance. She quickly moved and stood in front of her long-gone friend. Her hand reached up to hold his face as she brought her eyes level to his. “Jace, can you hear me?” she questioned calmly. Nothing. It was like she was made of glass and he was looking straight through her. She hesitated, knowing her next word would either snap him back or push him further away, “Jonathan?” He jumped, startled by the girl in front of him. She breathed a sigh of relief, “Where’d you go?” He didn’t answer her. He just looked at the floor as tears waterfalled from both eyes. Isabelle and Alec sat beside him, comforting him quietly. 

Both twins refused to leave his side that night, sandwiching him between them as they slept. Right on schedule, Jace awoke screaming. Alec, an insanely heavy sleeper, didn’t move a muscle. Isabelle, however, shot up a split second after Jace. This time was unlike any she had ever seen before. He was absolutely terrified, suffering a full-blown panic attack. She quickly pulled him against her, holding him like she was protecting him from the universe’s darkest demons. “You’re okay,” she whispered softly, “I’m right here. He can’t hurt you.” Her shirt was wet with his tears. 

A long time passed and Jace was still hysterical with no signs of getting better. She pulled back slightly and lifted his chin to look at her. He closed his eyes. “Look at me Jace,” her voice was soft yet stern. He did as he was told. Isabelle had never seen him so broken; the sight had her fighting back tears of her own. She knew she couldn’t promise him that nothing would hurt him, because given their family and their line of work, that would never be true. But there was one promise she could make him with absolute certainty. “Listen to me. You aren’t alone anymore; for as long as I live, you never will be. Your demons are our demons, and we will fight them together. Whenever you need me, I’ll be there. Understand?” Her words meant the world to him. He’d never dreamed that someone could possibly care about him this much, or at all. He didn’t know what to say. “Do you trust me?” she asked sincerely. His response was immediate, “With my life.” 

Isabelle released his chin and squeezed him as tight as she could. He squeezed back even harder, “Thank you for this… For everything. I don’t deserve you.” He lowered his head, feeling like such a burden. “Hey,” she snapped, looking at him with a fiercely serious face, “don’t you dare say that. You deserve the world, and I am so blessed to be the one to show it to you.” She was heartbroken that he would think himself a burden. It was quite the opposite; he had given her, and Alec’s lives a purpose. They depended on him just as much as he depended on them. Isabelle knew that Jace’s insecurities couldn’t be cured in day. Valentine had spent ten years digging them into him. But she would tell him how much he was worth every day for the rest of his life if that’s what it took.

“Did you really mean what you said before?” Jace asked, terrified she’d take it back. “That you’ll never leave me?” He was disgusted by how weak he felt as he asked her that, but he needed to hear it again. The look on his face shattered her to pieces, bringing out her most protective instincts. For the first time, she really stopped to realize how much the golden-haired boy meant to her. It had always been her and Alec vs. the world, but this broken soul had made his way into both their hearts. “Never,” she replied with absolute certainty. 

Jace sighed, “I suppose I owe you an explanation for why I’m always waking you up in the middle of the night.” Isabelle looked confused, “I know why. I told you, Alec gets nightmares too. They’re always about are father. And yours are obviously about Valentine.” Jace looked at her, completely vulnerable, “No, I mean exactly why. Full disclosure.” She grabbed his hand, “You don’t owe me that. You don’t owe me anything. If, one day, you want to tell me then I will be right here ready to listen. Until then, I will continue to care for you without question. My desire to do so is not conditional.” Jace breathed a sigh of relief, “I’m tortured by the memories of my father. Even when I’m awake. The things he did to me…” Jace paused, “I’m not ready to talk about the specifics, but it was bad Isabelle, really, really bad. The scary thing is, when I’m asleep they’re not just memories. It’s like I’m living it all over again… It’s so real and I feel every bit of it.” 

Isabelle didn’t know what to say; there were no words that could fix that. “I know I can’t take those memories away, no matter how much I want to, but I promise to give you one good memory for every horrible one he left behind.” She had an idea, “What if you moved into our room? At least that way you never have to sleep alone.” Every part of Jace wished that were possible, especially after tonight. He knew that tomorrow his room would seem even more lonely and cold now that he knew what it felt like to be with both Isabelle and Alec. But he shook his head, “Robert and Maryse would never let that happen.” Isabelle smiled, “You’d be surprised. I can almost guarantee that they care more about having the extra room than they care where we sleep. I’ll find some way to spin it in their favor and ask them about it tomorrow.” Jace looked scared. “Don’t worry,” she assured him, “I’ll make sure they know the whole thing was my idea.” Jace hated the thought of her confronting her parents in a way that might get her in trouble. But he also trusted that she wouldn’t do it if she thought they’d get angry.

Jace chuckled. Isabelle looked at him, puzzled, “What?” Jace smiled at her, “You’re just so… _you_. You come rushing in here in the middle of the night every time I wake you up with my stupid nightmares, and that still doesn’t stop you from offering to share your room with me. And not just that… you’ve sat here for the last hour and listened to me be embarrassingly weak and pathetic and you’re not even laughing at me.” Isabelle frowned, “You’re not weak, and I would never laugh at you.” Jace let out another small laugh, “There you go again.”

~*~*~

The first night that Jace had moved into their room he couldn’t sleep, there were too many thoughts racing through his mind. “Isabelle?” Jace whispered quietly to see if she was still up. He sounded scared and insecure. She turned to look at him, wide awake. “Is everything okay?” she asked. “Yeah, I just… Can I come talk to you?” he asked shyly. “Of course,” she replied, scooting over and holding up her blanket for him to come join. He nervously slid in next to her, not sure how to ask what was on his mind without sounding weak. 

Isabelle was quick to notice the slight change in his breathing, one he hadn’t even noticed himself. “Hey, are you okay?” she asked a second time, now sounding much more concerned. “If you’re uncomfortable in here, you can go sleep in your old room. They haven’t given it to anyone else yet.” Jace shook his head nervously. “No. Please no,” he begged, cringing at how pathetic he sounded, but he couldn’t help himself. “Please don’t make me leave.” He wrapped his arms around her. As irrational as he knew it was, he couldn’t help being afraid that if he let go, he would be sent away and would never see her or Alec ever again. “Oh Jace,” she said with concern, hugging him back tightly, “I don’t want you to leave. I am so happy to have you here, I just don’t want you to feel uncomfortable.” He was embarrassed at his own insecurity, “I’m sorry. I’m just a little overwhelmed.” “By what?” she asked patiently. 

Jace took a deep breath. “I spent all of my life thinking I would be alone forever. That it would be just me and Valentine; every minute would be dark, and I’d never feel any sense of purpose or direction. I’ve always had this emptiness, though I never knew exactly where it came from… Not until the night you first came in my room. That night was the first time in my life that anyone ever cared about me. It felt unlike anything I had ever imagined, and that emptiness got a little smaller. It continued to shrink every time you came back. And then, the other night… when you said all those things about how I’d never be alone… The emptiness was gone; I finally felt whole.” Jace paused as he tried to muster up the courage to say what he really wanted to say, “Just… never let me go, Isabelle. I know there are so many people that are far more deserving of your affection, but I’m the one who needs it the most,” he sheepishly confessed. “I don’t know what would happen if lost this… lost you. I haven’t known many people besides you and Alec, but I know that the way you are, the love you have for each other, it’s something special… unique. I am almost certain that I could search my whole life and never find anyone like you two, and I never want to be without you again.”

Isabelle was silent. Jace turned to look at her and saw tears streaming down her face. “What?” he asked, looking scared. “Did I say something wrong?” Isabelle turned and looked at him, “Not at all. Thank you for telling me all that, for being honest with me. I know it isn’t easy.” She held his face, “Make me a promise. Promise that you’ll always be honest with me, that you’ll never hide how you really feel.” 

The thought of being so open was terrifying, but for some reason he felt comfortable being vulnerable to her. “I promise.” She continued to hold his face, “How do you feel right now, Jace?” He hesitated for a moment, “I’m scared. Scared of messing up and pushing you and Alec away.” She smiled kindly at him. Jace was confused, “What?” She chuckled softly at his innocence, “You’re family now. You couldn’t be rid of us even if you wanted to.” Jace ‘s face fell into a deep sadness. “But I’m not family… not really. I’ll never be like you and Alec.” 

Isabelle looked at him with a heavy heart before climbing out of bed and grabbing a Sharpie. She lifted the bottom of his shirt and began drawing something on his abdomen. He tensed, feeling awkward and exposed. When she was done, she moved his shirt back down before he could see it. “You’re my brother now, just as much as Alec, and one day, when we’re old enough, you’ll be my parabatai. Then you’ll share my soul too.” She lifted his shirt back up showing the rune she had drawn on his skin, before proceeding to draw one on herself. Jace looked at her with complete disbelief, “You really want _me_ to be your parabatai?” “Absolutely,” she responded, sounding undeniably sure. “Why?” he pressed, still not believing her. This time she held his face with both her hands, “Because I love you.”

Jace froze. He gave her a look she’d never seen before. “You… You _love_ me?” Her confidence didn’t fade or falter, “Yes. So, this whole ‘being cared about thing’, you better get used to it.” Jace was still frozen. Isabelle let go of his face and looked at him patiently, “How do you feel now?” Jace had to think for a moment. He couldn’t compare this feeling to anything else he’d ever experienced. Part of him was scared. _To love is to destroy, and to be loved is to be destroyed._ Valentine’s words echoed in his mind. But, to his surprise, Isabelle’s words began to cover his father’s. _Because I love you._ Fuck it. If being loved meant he would be destroyed, then it was a price he was willing to pay; he was already pretty messed up anyways. “Loved,” he finally responded. Isabelle smiled, resuming her place by his side. He curled up around her and placed his head on her chest. He listened to her heartbeat to prove to himself that this wasn’t his imagination, that she was really there. Not that he could have ever imagined this even if he tried. She ran her fingers through his hair, as he repeated her words in his head over and over until he fell asleep. 

For the rest of his life, whenever he felt hopeless, unworthy, or unloved, he went back to that moment. When he felt like giving up, like he wanted to die, it was those words that kept him alive. No matter what happened between him and his siblings, nothing would ever change or compare to the love he felt for them. From then on, it was the three of them against the world. And he wouldn’t have it any other way.

**Author's Note:**

> Thank you for reading it all the way through! This isn't the style I usually write in (it's usually more like a script) but I'm trying to make it a little more readable. I hope it helped!
> 
> Please leave comments!!! I can't wait to hear from you!!!


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